[Kubernetes] Add ability to setup high availability Kubernetes master on testbed server

ansible/doc/README.testbed.k8s.Setup.md

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+# SONiC Kubernetes Design
+
+This document describes the design to test Kubernetes features in SONiC. 
+
+## Background
+
+Each SONiC DUT is a worker node managed by a High Availability Kubernetes master. The High Availability Kubernetes master is composed of three master node machines and one load balancer machine.
+
+By connecting each SONiC DUT to HA Kubernetes master, containers running in SONiC can be managed by the Kubernetes master. SONiC containers managed by the Kubernetes master are termed to be running in "Kubernetes mode" as opposed to the original "Local mode." 
+
+In Kubernetes mode, SONiC container properties are based on specifications defined in the associated Kubernetes manifest. A Kubernetes manifest is a file in the Kubernetes master that defines the Kubernetes object and container configurations. In our case, we use Kubernetes Daemonset objects. The Kubernetes Daemonset object ensures that each worker node is running exactly one container of the image specified in the Daemonset manifest file.  
+
+For example, in order to run SNMP and Telemetry containers in Kubernetes mode, we must have two manifests that define two Kubernetes Daemonset objects- one for each container running in "Kubernetes mode." 
+
+The following is a snippet of the Telemetry Daemonset manifest file that specifies the Kubernetes object type and container image:
+
+```
+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: telemetry-ds
+spec:
+  template:
+    metadata:
+      labels:
+        name: telemetry
+    spec:
+      hostname: sonic
+      hostNetwork: true
+      containers:
+      - name: telemetry
+        image: sonicanalytics.azurecr.io/sonic-dockers/any/docker-sonic-telemetry:20200531
+        tty: true
+            .
+            .
+            .
+```
+
+
+## Topology Overview
+
+In order to connect each SONiC DUT to a High Availability Kubernetes master, we need to set up the following topology: 
+![alt text](https://github.com/isabelmsft/k8s-ha-master-starlab/blob/master/k8s-testbed-linux.png)
+- Each high availability master setup requires 4 new Linux KVMs running on a Testbed Server via bridged networking.
+    - 3 Linux KVMs to serve as 3-node high availability Kubernetes master
+    - 1 Linux KVM to serve as HAProxy Load Balancer node    
+- Each KVM has one management interface assigned an IP address reachable from SONiC DUT.
+- HAProxy Load Balancer proxies requests to 3 backend Kubernetes master nodes. 
+
+Our setup meets Kubernetes Minimum Requirements to setup a High Available cluster. The Minimum Requirements are as follows:
+- 2 GB or more of RAM per machine
+- 2 CPUs or more per machine
+- Full network connectivity between all machines in the cluster (public or private network)
+- sudo privileges on all machines
+- SSH access from one device to all nodes in the system
+
+## How to Setup High Availability Kubernetes Master
+
+1. Prepare Testbed Server and build and run `docker-sonic-mgmt` container as described [here](https://github.com/Azure/sonic-mgmt/blob/master/ansible/doc/README.testbed.Setup.md) 
+2. Allocate 4 available IPs reachable from SONiC DUT.
+3. Update [`ansible/k8s-ubuntu`](../k8s-ubuntu) to include your 4 newly allocated IP addresses for the HA Kubernetes master and IP address of testbed server.
+
+  - We will walk through an example of setting up HA Kubernetes master set 1 on server 19 (STR-ACS-SERV-19). The following snippets are the relevant portions from [`ansible/k8s-ubuntu`](../k8s-ubuntu).
+
+   ```
+   k8s_vm_host19:
+     hosts:
+       STR-ACS-SERV-19:
+         ansible_host: 10.251.0.101
+  ```
+  - Replace `ansible_host` value above with the IP address of the testbed server.
+
+  ```
+  k8s_vms1_19:
+  hosts:
+    kvm19-1m1:
+      ansible_host: 10.250.0.2
+      master: true
+      master_leader: true
+    kvm19-1m2:
+      ansible_host: 10.250.0.3
+      master: true
+      master_member: true
+    kvm19-1m3:
+      ansible_host: 10.250.0.4
+      master_member: true
+      master: true
+    kvm19-1ha:
+      ansible_host: 10.250.0.5
+      haproxy: true 
+  ```
+
+  - Replace each `ansible_host` value with an IP address allocated in step 2. 
+
+  - Take note of the group name `k8s_vms1_19`. At the bottom of [`ansible/k8s-ubuntu`](../k8s-ubuntu), make sure that `k8s_server_19` has its `host_var_file` and two `children` properly set: 
+
+```
+k8s_server_19:
+  vars:
+    host_var_file: host_vars/STR-ACS-SERV-19.yml
+  children:
+    k8s_vm_host19:
+    k8s_vms1_19:
+```
+
+4. Update the server network configuration for the Kubernetes VM management interfaces in [`ansible/host_vars/STR-ACS-SERV-19.yml`](../host_vars/STR-ACS-SERV-19.yml).
+    - `mgmt_gw`: ip of the gateway for the VM management interfaces
+    - `mgmt_prefixlen`: prefixlen for the management interfaces
+5. If necessary, set proxy in [`ansible/group_vars/all/env.yml`](../group_vars/all/env.yml)
+6. Update the testbed server credentials in [`ansible/group_vars/k8s_vm_host/creds.yml`](../group_vars/k8s_vm_host/creds.yml).   
+7. If using Azure Storage to source Ubuntu 18.04 KVM image, set `k8s_vmimage_saskey` in [`ansible/vars/azure_storage.yml`](../vars/azure_storage.yml). Alternatively, manually download and store the Ubuntu 18.04 qcow2 image file at the path `/home/azure/ubuntu-vm/images/bionic-server-cloudimg-amd64.qcow2` on your testbed server.
+8. From `docker-sonic-mgmt` container, `cd` into `sonic-mgmt/ansible` directory and run `./testbed-cli.sh -m k8s-ubuntu [additional OPTIONS] create-master <k8s-server-name> ~/.password`
+   - `k8s-server-name` corresponds to the group name used to describe the testbed server in the [`ansible/k8s-ubuntu`](../k8s-ubuntu) inventory file, of the form `k8s_server_{unit}`. 
+   - Please note: `~/.password` is the ansible vault password file name/path. Ansible allows users to use ansible-vault to encrypt password files. By default, this shell script requires a password file. If you are not using ansible-vault, just create an empty file and pass the file name to the command line. The file name and location are created and maintained by the user.
+   - For HA Kubernetes master set 1 running on server 19 shown above, the proper command would be: 
+`./testbed-cli.sh -m k8s-ubuntu create-master k8s_server_19 ~/.password` 
+  - OPTIONAL: We offer the functionality to run multiple master sets on one server. 
+    - Each master set is one HA Kubernetes master composed of 4 Linux KVMs. 
+    - Should an additional HA master set be necessary on an occupied server, add the option `-s <msetnumber>`, where `msetnumber` would be 2 if this is the 2nd master set running on `<k8s-server-name>`. Make sure that [`ansible/k8s-ubuntu`](../k8s-ubuntu) is updated accordingly. `msetnumber` is 1 by default. 
+
+
+9. Join Kubernetes-enabled SONiC DUT to cluster (kube_join function to be written).
+
+
+#### To remove a HA Kubernetes master:
+- Run `./testbed-cli.sh -m k8s-ubuntu [additional OPTIONS] destroy-master <k8s-server-name> ~/.password`
+- For HA Kubernetes master set 1 running on server 19 shown above, the proper command would be: 
+`./testbed-cli.sh -m k8s-ubuntu destroy-master k8s_server_19 ~/.password` 
+
+## Testing Scope
+
+This setup allows us to test the following: 
+- Successful deployment of SONiC containers via manifests defined in master
+- Expected container behavior after the container is intentionally or unintentionally stopped
+- Switching between Local and Kubernetes management mode for a given container
+  - Addition and removal of SONiC DUT labels
+- Changing image version in middle of Daemonset deployment
+
+During each of the following states:
+- When all master servers are up and running
+- When one master server is down
+- When two master servers are down
+- When all master servers are down
+
+Down: shut off, disconnected, or in the middle of reboot
+
+
+In this setup, we do not consider load balancer performance. For Kubernetes feature testing purposes, HAProxy is configured to perform vanilla round-robin load balancing on available master servers.
+
+
+## How to Create Tests
+Each manifest is a yaml file
+
+CLI to make changes to manifest files
+
+pytests to apply manifest changes and check status

ansible/group_vars/k8s_ubu/creds.yml

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+---
+ansible_ssh_user: ubuntu
+ansible_ssh_pass: admin
+ansible_become: True
+become_method: sudo
+ansible_become_password: admin

ansible/group_vars/k8s_vm_host/creds.yml

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+---
+ansible_user: use_own_value
+ansible_password: use_own_value
+ansible_become_password: use_own_value

ansible/group_vars/k8s_vm_host/main.yml

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+k8s_root_path: /home/azure/ubuntu-vm
+k8s_vm_images_url: https://acsbe.blob.core.windows.net/vmimages
+k8s_hdd_image_filename: bionic-server-cloudimg-amd64.qcow2
+k8s_skip_image_downloading: false

ansible/host_vars/STR-ACS-SERV-19.yml

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+mgmt_bridge_k8s: br1
+mgmt_prefixlen_k8s: use_own_value
+mgmt_gw_k8s: use_own_value

ansible/host_vars/STR-ACS-SERV-20.yml

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+mgmt_bridge_k8s: br1
+mgmt_prefixlen_k8s: use_own_value
+mgmt_gw_k8s: use_own_value

ansible/k8s-ubuntu

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+all:
+  children:
+    k8s_vm_host:
+      children:
+        k8s_vm_host19:
+        k8s_vm_host20:
+    k8s_ubu:
+      children:
+        k8s_vms1_19:
+        k8s_vms2_19:
+        k8s_vms1_20:
+        k8s_vms2_20:
+    k8s_servers:
+      children:
+        k8s_server_19:
+        k8s_server_20:
+
+
+k8s_vm_host19:
+  hosts:
+    STR-ACS-SERV-19:
+      ansible_host: 10.251.0.101
+
+k8s_vm_host20:
+  hosts:
+    STR-ACS-SERV-20:
+      ansible_host: 10.251.0.102
+
+k8s_vms1_19:
+  hosts:
+    kvm19-1m1:
+      ansible_host: 10.251.0.103
+      master: true
+      master_leader: true
+    kvm19-1m2:
+      ansible_host: 10.251.0.104
+      master: true
+      master_member: true
+    kvm19-1m3:
+      ansible_host: 10.251.0.105
+      master_member: true
+      master: true
+    kvm19-1ha:
+      ansible_host: 10.251.0.106
+      haproxy: true 
+
+k8s_vms2_19:
+  hosts:
+    kvm19-2m1:
+      ansible_host: 10.251.0.107
+      master: true
+      master_leader: true
+    kvm19-2m2:
+      ansible_host: 10.251.0.108
+      master: true
+      master_member: true
+    kvm19-2m3:
+      ansible_host: 10.251.0.109
+      master_member: true
+      master: true
+    kvm19-2ha:
+      ansible_host: 10.251.0.110
+      haproxy: true 
+
+k8s_vms1_20:
+  hosts:
+    kvm20-1m1:
+      ansible_host: 10.251.0.111
+      master: true
+      master_leader: true
+    kvm20-1m2:
+      ansible_host: 10.251.0.112
+      master: true
+      master_member: true
+    kvm20-1m3:
+      ansible_host: 10.251.0.113
+      master_member: true
+      master: true
+    kvm20-1ha:
+      ansible_host: 10.251.0.114
+      haproxy: true 
+
+k8s_vms2_20:
+  hosts:
+    kvm20-2m1:
+      ansible_host: 10.251.0.115
+      master: true
+      master_leader: true
+    kvm20-2m2:
+      ansible_host: 10.251.0.116
+      master: true
+      master_member: true
+    kvm20-2m3:
+      ansible_host: 10.251.0.117
+      master_member: true
+      master: true
+    kvm20-2ha:
+      ansible_host: 10.251.0.118
+      haproxy: true 
+
+# The groups below are helper to limit running playbooks to specific server(s) only
+k8s_server_19:
+  vars:
+    host_var_file: host_vars/STR-ACS-SERV-19.yml
+  children:
+    k8s_vm_host19:
+    k8s_vms1_19:
+
+k8s_server_20:
+  vars:
+    host_var_file: host_vars/STR-ACS-SERV-20.yml
+  children:
+    k8s_vm_host20:
+    k8s_vms1_20:
+

ansible/roles/k8s_haproxy/tasks/main.yml

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+- name: update apt cache
+  apt: update_cache=yes cache_valid_time=3600
+  environment: "{{ proxy_env | default({}) }}" 
+
+- name: Install haproxy
+  apt: name=haproxy state=present
+  environment: "{{ proxy_env | default({}) }}" 
+
+- name: Enable init script
+  replace: dest='/etc/default/haproxy'
+         regexp='ENABLED=0'
+         replace='ENABLED=1'
+
+- name: Setup haproxy config file
+  template:
+    src: haproxy.j2
+    dest: /etc/haproxy/haproxy.cfg
+    backup: yes
+
+- name: Restart HAProxy
+  become: yes
+  service: name=haproxy state=restarted

ansible/roles/k8s_haproxy/templates/haproxy.j2

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+#---------------------------------------------------------------------
+global
+    # to have these messages end up in /var/log/haproxy.log you will
+    # need to:
+    #
+    # 1) configure syslog to accept network log events.  This is done
+    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
+    #    /etc/sysconfig/syslog
+    #
+    # 2) configure local2 events to go to the /var/log/haproxy.log
+    #   file. A line like the following can be added to
+    #   /etc/sysconfig/syslog
+    #
+    #    local2.*                       /var/log/haproxy.log
+    #
+    log         127.0.0.1 local2
+
+    chroot      /var/lib/haproxy
+    pidfile     /var/run/haproxy.pid
+    maxconn     4000
+    user        haproxy
+    group       haproxy
+    daemon
+
+    # turn on stats unix socket
+    stats socket /var/lib/haproxy/stats
+
+#---------------------------------------------------------------------
+# common defaults that all the 'listen' and 'backend' sections will
+# use if not designated in their block
+#---------------------------------------------------------------------
+defaults
+    mode                    http
+    log                     global
+    option                  httplog
+    option                  dontlognull
+    option http-server-close
+    option forwardfor       except 127.0.0.0/8
+    option                  redispatch
+    retries                 3
+    timeout http-request    10s
+    timeout queue           1m
+    timeout connect         10s
+    timeout client          1m
+    timeout server          1m
+    timeout http-keep-alive 10s
+    timeout check           10s
+    maxconn                 3000
+
+#---------------------------------------------------------------------
+# main frontend which proxys to the backends
+#---------------------------------------------------------------------
+frontend k8s-api
+   bind 0.0.0.0:80
+   mode tcp
+   option tcplog
+   default_backend k8s-api
+
+#---------------------------------------------------------------------
+# round robin balancing between the various backends
+#---------------------------------------------------------------------
+backend k8s-api
+   mode tcp
+   option tcplog
+   option tcp-check
+   balance roundrobin
+   default-server inter 10s downinter 5s rise 2 fall 2 slowstart 60s maxconn 250 maxqueue 256 weight 100
+
+       {% for host in groups['k8s_vms' + msetnumber + '_' + servernumber] %}
+       {% if hostvars[host].master is defined %}
+         server {{ hostvars[host].inventory_hostname }} {{ hostvars[host].ansible_host }}:6443 check
+       {% endif %}
+       {% endfor %}